1. Field of the Invention
This disclosure relates to servicing a wellbore. More specifically, it relates to servicing a wellbore with compositions comprising a polysaccharide based cement additive and methods of making same.
2. Background of the Invention
Natural resources such as gas, oil, and water residing in a subterranean formation or zone are usually recovered by drilling a wellbore down to the subterranean formation while circulating a drilling fluid in the wellbore. After terminating the circulation of the drilling fluid, a string of pipe, e.g., casing, is run in the wellbore. The drilling fluid is then usually circulated downward through the interior of the pipe and upward through the annulus, which is located between the exterior of the pipe and the walls of the wellbore. Next, primary cementing is typically performed whereby a cement slurry is placed in the annulus and permitted to set into a hard mass (i.e., sheath) to thereby attach the string of pipe to the walls of the wellbore and seal the annulus. Subsequent secondary cementing operations may also be performed.
Wellbore servicing fluids (e.g., cement slurries, fracturing fluids, drilling fluids) are often modified to allow them to function for their intended purpose under a variety of conditions. These modifications typically involve the inclusion of additives in the wellbore servicing fluids. For example, cement compositions can be modified using additives such as dispersants, fluid loss control agents, viscosifiers, premature gelation inhibitors, transition time modifiers and the like.
Additives such as dispersants and fluid loss control agents are often formulated from materials that are deemed environmentally unacceptable for use in locations subject to stringent environmental regulations. Their status as unacceptable environmental materials stems from their inability to undergo complete biodegradation in the environment which may result in undesirable effects if the materials are released into the environment or if they accumulate in animal and plant tissues for long periods. Thus, it would be desirable to develop biodegradable additives that function as dispersants, fluid loss agents, viscosifiers, gelation inhibitors, transition time modifiers and the like.